Patent GB-190624937-A (GB)
Title: Improvements in Weighing Machines
Inventor: MCLEOD CLIFFORD JOHN
Filed: 1906-11-06
Granted: 1907-04-18
Abstract: 24,937. McLeod, C. J. Nov. 6. Platformmachines ; compound-lever and steelyard apparatus.-Relates to coin-controlled weighing-machines of the platform type having a pivoted scale beam, upon the bars of which one or more weights are moved automatically, the weights being locked in position when indicating the weight upon the platform, and returned automatically to their original positions when released. The scale beam comprises parallel bars 1, 2, Fig. 3, connected by a plate 3 and by a pair of plates 4, and supported by a post 7 on the frame 8. Weights 5, 6 move along the bars 1, 2 and normally occupy the positions shown in Fig. 3, the beam then being inclined so that the weights move to the end 4 by gravity. The parts connecting the beam to the platform 16, Fig. 2, comprise links 9, 10, lever 11 pivoted to the lug 12, rod 13, forked levers 14, 21, and rods 17, 19. One end of the lever 21 is connected by links 23 to the outer ends of a forked lever 24, pivoted at 25 and connected at the opposite end to a bar 26 extending upwards through the column of the machine. The bar 26 carries a spring-supported rod 29 pivotally connected at its upper end to one arm 31 of a bell-crank lever pivoted at 32 to a depending portion of the frame 8, the other arm 34 of the lever being notched to act as a toggle member with the arm 35 of a dog pivoted at 38 to the lever 27, and comprising arms 35, 36, 37. When a person steps on the platform, the bar 26, in rising, moves the arm 34 to the right, the arms 34, 35 act as toggle-levers, and the lever 27 is thereby raised, but falls again when the arm 35 has moved sufficiently to the right to disengage the arm 34. The dog returns to its normal position when the bar 26 descends. The coin-freed mechanism consists of a receptacle 40 carried by a long arm 39 connected to a short arm 41 on a shaft 42, which also carries a weighted arm 43 and an arm 44 connected by a link 45 to the lower end of an arm 46 pivoted at 47. A detent 48 pivoted at 47 carries a pin 49, which rests against, and is moved by the arm 46, and is notched to engage, and prevent upward movement of the arm 31. If a person steps on the platform and does not deposit a coin, the bar 26 is raised and the spring 30 is compressed, but the rod 29 is prevented from rising. The bar 26 is locked in the elevated position, to prevent unnecessary movement of the parts, by an arm 50 pivoted to a frame 33 at 51, also pivotally connected to the bar 26 at 52, and engaging a pivoted latch 53 which supports the bar in the elevated position until released by the coin. The releasing-mechanism comprises an arm 54 to be engaged by the arm 36 of the pivoted dog. The function of the lever 27 is to lift the scale beam by means of a bar 55 to cause the weights 5, 6 to move along the bars, the weight on the platform also tending to lift the beam by pulling downwards the plate 3. The beam is retained in the elevated position by means of a pivoted prop 56, carrying at its upper end two flat springs 58, 59, Fig. 9, and having a short arm 60 in contact with a spring- controlled pin 61, which is operated by means of an arm 62 to move the prop towards the right simultaneously with the rising of the beam, so that the beam is supported by a stud 63 resting upon the springs when the lever 27 descends. The weight 6 is locked at the outer end of the beam by a gravity catch 64 engaging the bar 55, and is liberated, to move along the bar, when the lever 27 descends. As the weight 6 moves inwards, the pressure on the springs 58, 59 is reduced until the position of balance is reached. The springs then raise the beam higher and release the locking- bar 65 to lock the weight in position. If this does not correspond with one of the ten-pound graduation marks into which the bar 2 is divided, the weight moves on to the next mark beyond, and is there locked by a tooth within the weight entering one of the notches in the bar 65. The locking- means comprises the bar 65 having its ends bent at right-angles and pivoted to the beam. A post 68 on a lever 69 pivoted at 70 normally holds the bar in a raised position, a pin 71 on the bar 26 engaging one end of the lever 69, and releasing the lever when the bar is raised by the weight of a person on the platform. The outer end of the bar 65 is still held in an elevated position by a device comprising a pivoted bell - crank lever having one arm 72, Figs. 7 and 8, extending beneath the bar 65 ; the second arm 73 carries a detent 74, projecting laterally through an opening 75 and working with a fixed detent 76, being normally on the right-hand side of, and below the fixed detent, Fig. 7. As the beam rises, the detent 74 passes over the top of the fixed detent 76, and the locking-bar 65 is released. An arm 78 on the weight 6 returns these parts to their normal positions when the weight itself returns. The scale beam is then further lifted by one of the springs 58, 59 to release the weight 5, which is normally locked at the outer end of the beam by means of a spring finger 79 held upwards against the weight by means of a rod 80, loosely connected at its lower end to the arm 72, and passing at its upper end through an opening in the bar 1. The spring 79 normally exerts a downward force on the rod 80, and tends to release the weight 5 ; but the rod is moved longitudinally to lock the weight, when the arm 73 is moved to the right by means of the rod 78 on the weight 6, and releases the weight as the beam rises. The weight 5 is locked in position on the bar 1 by means of a bar 81, supported at one end by a rod 82 extending from the bar 65, and at the opposite end by a device comprising a pivoted detent lever provided with a cam 83 upon which the bar 81 rests, and an arm 84 carrying a detent 85 projecting through one of the plates 4 and working with a fixed detent 86, being normally on the left hand side of, and below the fixed detent. Both the fixed detent, and a pivoted lever 87 bearing against pins in the arms 73, 84, in turn hold the bar 81 in the unlocked position ; but, as the beam rises, due to the weight 5 moving inwards, the detent 85 clears the fixed detent, and the bar 81 falls to lock the weight in position. The parts return to their normal positions when the person leaves the platform. The plate 8 is pivoted at 88, Figs. 1 and 3, and is self-adjusting, being provided with a balance-weight 33 The frame-plate 8 is locked in the position it occupies when a person steps upon the platform by means of a tooth on a lever 90, operated from the platform through a pin 92 on the bar 26 and a spring 91, engaging a serrated edge on a plate 89 attached to the plate 33. The lever 90 is locked in position by a lug 95 engaging the arm 94 of a bell-crank lever, the other arm 96 of which is connected by mechanism 97, 98, 99 to a pivoted lever 100. The weight 6, in returning to its normal position, engages the lever 100 and disengages the arm 94 from the lug 95 to set free the plate 33.